Inflammation of Vermiform Appendix

Updated: Aug 23, 2023
Author: Steven L Lee, MD; Chief Editor: John Geibel, MD, MSc, DSc, AGAF 


Practice Essentials

Acute appendicitis remains one of the most common surgical diseases encountered by physicians. The classic presentation includes a history of initial periumbilical or epigastric abdominal pain migrating to the right lower quadrant (RLQ). The pain is gradual in onset and progressively worsens. Anorexia, nausea, and vomiting are typically associated with the disease. When appendicitis manifests in its classic form, it is easily diagnosed and treated, and as a rule, no imaging studies are necessary.

Unfortunately, the classic symptoms occur in just over half of patients with acute appendicitis. Atypical presentations often lead to a delay in diagnosis, perforation, prolonged hospitalization, and increased morbidity. Consequently, accurate and timely diagnosis of atypical appendicitis remains clinically challenging, and this condition is still one of the most commonly missed problems in the emergency department. Controversy continues over the most accurate, cost-effective, and rapid method of making the diagnosis of atypical appendicitis. Surgical consultation remains the most effective method of determining what additional diagnostic tools are needed.

There is growing interest in treatment of acute appendicitis with antibiotics without appendectomy,[1] as well as in the use of biomarkers to improve the accuracy of diagnosis. Endoscopic retrograde appendicitis therapy (ERAT) is an organ-sparing intervention that has been suggested as a potential alternative to appendectomy in acute uncomlicated appendicitis.[2]

For patient education resources, see the Digestive Disorders Center, as well as Appendicitis and Abdominal Pain in Adults.


Embryologically, the appendix is a continuation of the cecum and is first delineated during the fifth month of gestation. The appendix does not elongate as rapidly as the rest of the colon, thus forming a wormlike structure.[3]

The average length of the appendix is 10 cm, but its length can range from 2 to 20 cm. The wall of the appendix consists of both an inner circular and an outer longitudinal layer of muscle. The longitudinal layer is a continuation of the taeniae coli. The appendix is lined by colonic epithelium.[3]

Few submucosal lymphoid follicles are noted at birth. These follicles enlarge, peak between age 12 and 20 years, then decrease. This correlates with the incidence of appendicitis.

Blood supply to the appendix is mainly from the appendicular artery, a branch of the ileocolic artery. This artery courses through the mesoappendix posterior to the terminal ileum. An accessory appendicular artery can branch from the posterior cecal artery. Damage to this artery can lead to significant intraoperative and postoperative hemorrhage and should be searched for carefully and ligated once the main appendicular artery is controlled.[4]

The base of the appendix is consistently located at the posteromedial wall of the cecum, about 2.5 cm below the ileocecal valve. This is also where the taeniae converge.[4]

While the appendiceal base is in a constant location, the position of the tip of the appendix varies widely. In 65% of patients, the tip is located in a retrocecal position; in 30%, it is located at the brim or in the true pelvis; and, in 5%, it is extraperitoneal, situated behind the cecum, ascending colon, or distal ileum. The location of the tip of the appendix determines early signs and symptoms of appendicitis.


Appendicitis progresses through four stages, as follows[4] :

  • Acute or focal appendicitis
  • Suppurative appendicitis
  • Gangrenous appendicitis
  • Perforated appendicitis

The basic pathophysiology of appendicitis is obstruction of the lumen of the appendix followed by infection. In 60% of patients, obstruction is caused by hyperplasia of the submucosal follicles. This form of obstruction is mostly observed in children and is known as catarrhal appendicitis. A fecalith or fecal stasis causes luminal obstruction 35% of the time and is usually observed in adults. Obstruction may also be caused by foreign bodies (4%) and tumors (1%).

Following obstruction, an increase in mucus production occurs, leading to increased intraluminal pressure. With increased pressure and stasis from obstruction, bacterial overgrowth ensues. The mucus then turns into pus that causes a further increase in luminal pressure. This leads to distention of the appendix and visceral pain, which is typically located in the epigastric or periumbilical region.

As the luminal pressure continues to increase, lymphatic obstruction occurs, leading to edema in the appendiceal wall. This stage is known as acute or focal appendicitis. The overlying parietal peritoneum becomes irritated, causing the pain to localize to the right lower quadrant (RLQ). This series of events results in the classic migrating abdominal pain described in patients with appendicitis.

Further increases in pressure lead to venous obstruction, causing edema and ischemia of the appendix. The ensuing bacterial invasion of the wall of the appendix is known as acute suppurative appendicitis. Finally, with continued pressure increases, venous thrombosis and arterial compromise occur, leading to gangrene and perforation.[4]

If the body successfully walls off the perforation, the pain may actually improve. However, symptoms do not completely resolve. Patients may still have underlying RLQ pain, decreased appetite, change in bowel habits (eg, diarrhea, constipation), or intermittent low-grade fever. If the perforation is not successfully walled off, then diffuse peritonitis develops.


Appendicitis results from obstruction of the lumen of the appendix. Obstruction may be due to lymphoid hyperplasia (60%), fecalith or fecal stasis (35%), foreign body (4%), or tumors (1%).[4]


In Western countries, approximately 7% of individuals develop appendicitis at some point during their lives. Approximately 200,000 appendectomies are performed annually in the United States.[3]

The annual incidence of acute appendicitis has gradually declined by nearly 50% from its peak incidence in the early 20th century to its current levels of 1 case per 1000 population in the United States and 86 cases for every 100,000 persons worldwide.[5, 6]

Acute appendicitis is less common in Africa and in parts of Asia because of the high-residue diets of the inhabitants.


The outcome following appendectomy for acute or suppurative appendicitis is excellent. Although most patients return to full activity within 2 weeks, prolonged hospitalization and additional diagnostic and therapeutic procedures may be required when perforated appendicitis is encountered.

The prognosis for all stages of appendicitis is excellent, with a mortality of less than 1%. This low death rate is largely the result of early diagnosis and treatment, antibiotics, and improved anesthesia care.

Numerous prospective randomized trials have compared laparoscopic appendectomy with open appendectomy. The two techniques have been found to be similar with respect to the negative appendectomy rate (laparoscopic, 14.4%; open, 14.5%), length of hospital stay (laparoscopic, 3 d; open, 3.7 d), and incidence of intra-abdominal abscess formation (laparoscopic, 1.9%; open, 0.8%).

Laparoscopic appendectomy appears to have a slightly lower wound infection rate (3%) than open appendectomy does (7.5%).[7]

The benefits of a laparoscopic approach seem to be more pronounced among obese patients. One study found a significantly shorter length of hospital stay (laparoscopic, 3.4 d; open, 5.5 d) and a higher wound closure rate (laparoscopic, 90%; open, 68%) in patients with a body mass index (BMI) higher than 30.[8]

Data from the Nationwide Inpatient Sample (NIS) from 2006 to 2008 demonstrated that laparoscopic appendectomy was associated with lower morbidity, lower mortality, and a shorter hospital stay in both perforated and nonperforated appendicitis. Laparoscopic appendectomy was also associated with lower hospital charges in patients with perforated appendicitis.[9]

Studies by Frazee et al suggested that in the setting of uncomplicated appendicitis, outpatient laparoscopic appendectomy is effective and safe, with low morbidity and low readmission rates.[10, 11]

A systematic review and meta-analysis by Neogi et al found that laparoscopic appendectomy had a better complication profile than open appendectomy even in children with complicated appendicitis.[12]

A retrospective cohort study (N = 450) by Basukala et al compared the outcomes of open (n = 300) and laparoscopic (n = 150) appendectomy and found that the laparoscopic procedure was associated with a significantly longer mean operating time (56.86 vs 46.08 min) but a shorter hospital stay (1.07 vs 1.28 d) and a shorter course of oral analgesics (3.00 vs 3.55 d).[13] The total number of complications was less in the laparoscopic group than in the open group, but there was no statistically significant difference in postoperative complications between the two groups.




Abdominal pain is the most common symptom of appendicitis and is present in nearly every patient with this condition. The classic presentation of a patient with appendicitis includes a history of initial periumbilical or epigastric abdominal pain migrating to the right lower quadrant (RLQ). The pain is gradual in onset and progressively worsens. Anorexia, nausea, and vomiting are typically associated with the disease.

The symptoms of appendicitis vary, depending on the location of the appendix. When the appendix is located anteriorly, the classic migratory pain is expected. In patients with a retrocecal appendix, however, a dull ache is often described. When the tip of the appendix is located in the pelvis, atypical pain is commonly encountered. Patients may report dysuria and urinary frequency due to the inflamed appendix irritating the bladder. Patients may also have diarrhea or tenesmus if the inflamed appendix is adjacent to the rectum.

In early appendicitis, the patient is initially afebrile or has a low-grade fever. Higher fevers are associated with a perforated appendix.

Neurogenic appendicopathy may mimic the clinical symptoms of acute appendicitis, but there will be no indications of acute inflammation on histopathology.[14] Compared with acute appendicitis, it is often associated with recurrent and longer-lasting abdominal pain.

Physical Examination

On physical examination, the patient is usually lying still; movement worsens the pain. Having the patient cough elicits localized pain in the RLQ. Local tenderness to palpation is usually observed. Percussion tenderness is also noted in this area. Children often have localized pain with walking and jumping. The Rovsing sign (pain in the RLQ during palpation of the left lower quadrant [LLQ]) has also been associated with appendicitis. This finding represents indirect tenderness due to peritoneal irritation localized to the RLQ.

Unfortunately, only 55% of patients with appendicitis present with the classic history and physical findings. This is because the early signs and symptoms are primarily dependent on the location of the tip of the appendix, which is highly variable.[4]

When the tip of the appendix is retrocecal, tenderness may be manifested by passive extension of the hip (psoas sign). When it is located in the pelvis, tenderness may be detected during rectal examination or pelvic examination. Thus, in patients with persistent abdominal pain and rectal symptoms (diarrhea or tenesmus), it is important to perform a rectal examination. If the appendix is lying adjacent to the obturator internus, pain may be manifested with flexion of the right hip and internal rotation. Testicular examination findings are typically normal.



Laboratory Studies

Complete blood count with manual differential

The white blood cell (WBC) count is often mildly elevated, and a left shift is present. In children, it is helpful to obtain a manual differential. When an extremely elevated WBC count is present, either the patient has a perforated appendix or another process (eg, a viral illness) is responsible.

In both pediatric and adult patients, the WBC count is not always elevated. Thus, an increased percentage of bands on manual cellular differential may be just as reliable. Because an accurate history and physical is often more difficult to obtain, a persistently elevated percentage of bands may be the only objective finding of appendicitis in pediatric patients.

C-reactive protein

The C-reactive protein (CRP) level is often elevated in patients with acute appendicitis. However, an exact cutoff point that can accurately discriminate between acute appendicitis and other pathology has not been determined.[15]


A study by Pogorelić et al suggested that hyperbilirubinemia could be useful as an indicator of perforated appendicitis in children.[16]


Although not mandatory, urinalysis is often done to rule out urinary tract infections; however, pyuria (WBCs in the urine) is commonly observed in appendicitis because the inflammatory process may lie adjacent to the right ureter.

Urine pregnancy test

Females of reproductive age with abdominal pain should undergo urine testing to rule out pregnancy.

Electrolyte and renal panel

This test is not required but may be useful to help guide electrolyte resuscitation prior to appendectomy.

Additional biomarkers

The biomarkers calprotectin (CP) and serum amyloid A (SAA) are also elevated in patients with acute appendicitis. As with CRP, exact cutoff points to assist in the diagnosis of acute appendicitis have not been determined.[17] Procalcitonin has not been shown to be helpful in diagnosing acute appendicitis, but it may have value in identifying perforated appendicitis.[15]  Plasma pentraxin-3 may have diagnostic value in the setting of acute appendicitis.[18]

Imaging Studies

In patients with classic appendicitis, no imaging studies are needed. This statement was confirmed by a retrospective study determining predictive values for appendicitis (Alvarado score) on the basis of history and physical findings. A prospective comparison of the accuracy of the Alvarado score with ultrasonographic (US) findings was similar.[19]

In the workup of atypical appendicitis, additional imaging studies may be required.[20] Controversy exists as to the most accurate, rapid, and cost-effective method of diagnosing atypical appendicitis while avoiding delays that may increase morbidity.

Plain abdominal radiography

For the most part, abdominal roentgenograms are not helpful in making the diagnosis of appendicitis. Roughly 85% of patients have normal radiographic findings, and 10% have nonspecific findings.[21] The two most common nonspecific findings associated with appendicitis are ileus and small-bowel obstruction. A more specific abnormality is a fecalith in the right lower quadrant (RLQ), but this is observed in only 4-5% of radiographs.

Other findings may include loss of the psoas shadow and deformity of the cecal outline. Rarely, free air under the diaphragm may also be present in patients with perforated appendicitis.

Abdominal/pelvic ultrasonography

US is an ideal noninvasive means of visualizing the abdominal cavity.[22, 23, 24] It is inexpensive and portable, and it can be rapidly performed with little or no patient preparation. Most important, it poses no ionizing radiation risk to the patient; therefore, it is particularly safe to use in children and pregnant women. On the other hand, US is operator-dependent, which means that it requires some experience and expertise to produce consistent quality results.

The wall elements of the appendix have a typical "target" appearance and can be visualized by using graded US compressive technique with a high-resolution transducer, occasionally supplemented with color Doppler.

Appendicitis is suspected when the study demonstrates wall thickening (>6 mm), luminal distention, and lack of compressibility. In addition, US is useful in detecting free intraperitoneal fluid and fluid collections consistent with abscess formation.

Prospective studies showed excellent results, with an average sensitivity of 86% and a specificity of 94% under the conditions of well-controlled clinical trials (and, therefore, experienced examiners).[25] In addition, many reported studies included patients with classic appendicitis instead of patients with equivocal clinical histories and physical findings.

Such good results reported in prospective clinical trials were not often duplicated in routine clinical conditions. In fact, US has proved no more accurate than clinical evaluation by a surgeon, and low sensitivity and high false-negative rates have been reported.[21, 26, 27]

In a study that included 275 pediatric patients, Prada Arias et al assessed the diagnostic accuracy of US for differentiating appendicitis (n = 132) from nonspecific acute abdominal pain (n = 143).[28] US had a sensitivity of 94.7% and a specificity of 87.4% for differentiating appendicitis, with a 12.6% false-positive rate and a 5.3% false-negative rate. There was a 17.4% false-negative rate in the perforated group, as well as a 6.3% false-negative rate in the high-risk group and a 12.2 false-positive rate in the low-risk group.

US is most useful for excluding other diagnoses. In women, pelvic pathology, such as pelvic inflammatory disease, ruptured graafian follicle, twisted ovarian cyst or tumor, endometriosis, and ruptured ectopic pregnancy can be readily detected by means of US.

US is of limited value when the appendix is not visualized. A negative ultrasound study without visualization of the appendix has a 10% risk of appendicitis. For inconclusive findings, the risk of appendicitis may be as high as 68%.[29]

Tang et al proposed a predictive model for complicated pediatric appendicitis in which US of the appendix was combined with measurement of laboratory inflammatory indicators, including WBC count, neutrophil percentage, neutrophil count, neutrophil-to-lymphocyte ratio (NLR), CRP, and procalcitonin.[30]  They found that CRP, NLR, the presence of an appendicolith, and peripheral retina echo enhancement were independent risk factors for complicated appendicitis in children.

Computed tomography with contrast

Findings on computed tomography (CT) become more prominent with enhanced disease.[23] Specific findings include an edematous and thick-walled appendix, inflammatory streaking of surrounding fat, and the presence of an appendicolith. Abscess formation, a small amount of free air in the RLQ, and a pericecal phlegmon suggest a perforated appendix.

In most clinical trials, CT has appeared superior to US for evaluating the acute abdomen. Because it has been shown to yield precise information, it has increasingly become a screening tool for acute appendicitis in the emergency department. In well-conducted clinical trials, CT has shown excellent sensitivity and specificity (87-100% and 91-97%, respectively).[31, 32, 33]

As with US, however, the good results reported in prospective clinical trials were rarely duplicated in routine clinical conditions. In one study, the use of CT in patients with acute appendicitis rose from 25% to 68% over a 5-year period, yet the rate of negative appendectomy remained largely unchanged, suggesting that the information obtained from imaging studies may not have much influence on the clinical decision-making process.[34]

One of the potential clinical dilemmas involves the failure of CT to identify a normal appendix. The accuracy of CT for identifying a normal appendix is in the range of 44-51% in asymptomatic patients.[35, 36] It is probably unsafe to assume that nonvisualization of the appendix excludes the diagnosis of acute appendicitis unless there is a collaborating history or physical findings. In a patient who has no evidence of inflammation in the ileocecal region and whose appendix is not visualized, there is still a chance that acute appendicitis is present.

In cases of suspected acute appendicitis where CT findings are equivocal, the use of clinical scoring systems may be diagnostically helpful.[37, 38]  Such systems include the Alvarado, Eskelinen, appendicitis inflammatory response, Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA), and adult appendicitis score (AAS) systems.

Magnetic resonance imaging

Magnetic resonance imaging (MRI) has been shown to assist in the evaluation of acute appendicitis. A dilated appendix (>7.5 mm[39] ) has been shown to be abnormal. MRI may be more helpful in diagnosing abdominal pain in pregnant women.[40]

Technetium-labeled white blood cell scan

Despite a reported sensitivity of 98% and specificity of 95%, the time required for performing the scan and its lack of around-the-clock availability make this a less-than-ideal diagnostic test for appendicitis.[41]

Barium contrast studies

Historically, a single-contrast barium enema was used to diagnose patients with atypical signs and symptoms. The goal was to assess the patency of the appendiceal lumen. In addition, the colonic wall could be examined for extrinsic mass effects caused by appendicitis. Although this remains a simple, inexpensive, and safe study, it has been largely supplanted by US and CT and is rarely used today.


With the exception of an open surgical exploration, the only diagnostic procedure for acute appendicitis is diagnostic laparoscopy.

Histologic Findings

A small percentage of normal-appearing appendices have focal appendicitis on microscopic examination. In addition, early appendicitis may be encountered in the form of increased interleukin (IL)-2 and tumor necrosis factor (TNF)-α secretion, which cannot be detected on gross examination. Approximately 1% of patients have appendicitis from carcinoid or adenocarcinoma.[21]



Approach Considerations

Indications for surgical consultation

A surgeon should evaluate any patient with classic migrating abdominal pain and right-lower-quadrant (RLQ) tenderness. Given that only a little more than half of patients with appendicitis present with a classic history and physical findings, acute appendicitis should be on the list of possible diagnoses for any patient with abdominal pain. Thus, a surgeon should also evaluate patients with focal RLQ tenderness or progressively worsening abdominal pain.

To minimize the time between presentation and appendectomy, surgical consultation should be obtained before additional diagnostic studies, such as computed tomography (CT) and ultrasonography (US), are performed.[21]

Indications for operation

Appendectomy is typically performed after the diagnosis of appendicitis is made. Patients with a classic history and physical examination findings, along with a normal urine analysis (or pyuria) and an elevated white blood cell (WBC) count with a left shift, usually do not need any additional imaging studies prior to appendectomy. Surgery is also indicated in patients with an atypical presentation and radiographic findings consistent with appendicitis.

Any patient with atypical abdominal pain who (1) experiences persistent pain and becomes febrile, (2) has a rising WBC count, or (3) exhibits worsening clinical examination findings should undergo diagnostic laparoscopy and appendectomy. In patients with an atypical presentation, serial physical examinations are the most important tool in deciding if a patient needs surgery. The WBC count often does not increase after the patient is admitted and hydrated; therefore, any patient sent home from the emergency department should undergo a follow-up evaluation the next day.[21]

Endoscopic retrograde appendicitis therapy (ERAT) is an organ-sparing intervention that has been suggested as a potential alternative to appendectomy in acute uncomlicated appendicitis.[2]

Contraindications for operation

No contraindications for appendectomy in patients with suspected appendicitis exist; however, patients with a well-developed abscess (detected on CT) following perforated appendicitis may be initially treated with percutaneous drainage and intravenous (IV) antibiotics.

Once bowel function resumes, the patient may be discharged on oral antibiotics (total IV plus oral antibiotics for 7-10 days) with consideration for interval appendectomy in 6 weeks.[42]

Medical Therapy

Although appendectomy is still the standard treatment, a meta-analysis by Wilms et al led to the conclusion that antibiotic treatment alone might be feasible in specific patients or conditions in which surgery is contraindicated, or in a well-designed randomized, controlled clinical trial.[43, 44] These findings suggest that once broad-spectrum IV antibiotics have been initiated, it is likely that the progression of disease has been halted or reversed.

The Appendicitis Acuta (APPAC) clinical trial was designed to compare antibiotic therapy (n = 257) with appendectomy (n = 273) for treatment of CT-confirmed uncomplicated acute appendicitis,[45]  the aim being to determine whether antibiotic treatment was noninferior to surgery (prespecified noninferiority margin, 24%). The primary end point for the surgery group was successful completion of appendectomy; that for the antibiotic group was hospital discharge without need for surgery and no recurrence of appendicitis over 1 year of follow-up.

On intent-to-treat analysis, there was a –27% difference in treatment efficacy between the two groups, favoring surgery.[45]  Thus, the researchers did not demonstrate antibiotic treatment to be noninferior to surgery according to the prespecified noniferiority margin. However, most patients randomized to antibiotic treatment for uncomplicated appendicitis did not require appendectomy during the 1-year follow-up period, and those who required appendectomy did not experience significant complications.

An analysis by Sceats et al that compared the relative long-term cost-effectiveness of (1) laparoscopic appendectomy, (2) inpatient nonoperative management, and (3) outpatient nonoperative the treatment of uncomplicated acute appendicitis found laparoscopy to be cost-effective and did not identify any scenarios in which nonoperative management was preferred.[46]

The COMMA trial, which was designed to evaluate the efficacy and quality of life associated with conservative (ie, antibiotic-only) treatment of acute uncomplicated appendicitis, found that such treatment was associated with higher recurrence rates and poorer quality of life.[47]  The authors stated that surgery should remain the treatment of choice for this condition.

Study findings suggest that appendectomy may be considered a semielective operation rather than an automatically urgent or emergency procedure, as it had been considered in the past. A retrospective study by Kim et al found that delayed appendectomy is safe for patients with acute nonperforated appendicitis.[48]  Other studies have produced similar results.[49]

Some studies have suggested that probiotics may play a role in the treatment of acute appendicitis, uncomplicated appendicitis in particular[50] ; however, further research is needed.

Surgical Therapy

Preparation for surgery

All patients diagnosed with appendicitis should be adequately hydrated with isotonic IV fluids. In addition, broad-spectrum IV antibiotics (ampicillin, gentamicin, and metronidazole or a third-generation cephalosporin and metronidazole) should be started prior to the operation. Newer single-agent broad-spectrum antibiotic regimens are at least as effective as the traditional triple therapy and may also be used.[51]

Antibiotics, analgesics, and antipyretics should not be administered to patients admitted for serial examinations, because these medications may mask the underlying disease process.

To minimize the time from presentation to appendectomy, surgical consultation should be obtained before additional diagnostic studies are obtained; these tests are often unnecessary.[21]

The basic technique for open and laparoscopic appendectomy is described below and is individualized to the authors' preference.[52] Other approaches, suture materials, or techniques may be used with equal success.

Open appendectomy


Most surgeons perform appendectomy through a RLQ incision over the McBurney point, located two thirds of the distance between the umbilicus and the anterior superior iliac spine.

The subcutaneous tissue and Scarpa fascia are dissected until the external oblique aponeurosis is identified. This aponeurosis is divided sharply along the direction of its fibers. A muscle-splitting technique is then used to gain access to the peritoneum. Although historically, intraoperative cultures of purulent peritoneal fluid were obtained, cultures have not been shown to be helpful at the time of initial operation.[53]

Delivery of appendix

Small Richardson retractors are placed into the peritoneum, and the cecum is identified and partially exteriorized with a moist gauze pad or Babcock clamp. The taeniae coli are followed to the point where they converge at the base of the appendix. The rest of the appendix is then brought into the field of vision. Gentle manipulation may be required to bluntly dissect any inflammatory adhesions.

Division of mesoappendix and ligation of appendix

Once the appendix is exteriorized, the mesoappendix is divided between clamps, divided, and ligated. The base of the appendix is clamped after milking potential fecaliths into the lumen of the appendix. The appendix is then tied off with a 0 polyglycolic acid suture. The appendix is amputated and passed off the field as a specimen.

The mucosa of the appendiceal stump may be cauterized to avoid future mucus production. Inverting the appendiceal stump is not necessary. The cecum and appendiceal stump are then placed back into the abdomen.

The pelvis and the right pericolic gutter are suctioned to remove any fluid. If no evidence of free perforation exists, further peritoneal lavage is not necessary and may be harmful; however, if free perforation is encountered, the authors prefer to thoroughly irrigate the abdomen with warm saline solution. A drain is not required unless an obvious cavity is present after drainage of a well-developed abscess.


The peritoneum is identified, and hemostats are placed on both apices and on the midpoints of the superior and inferior sides. The peritoneum is closed with a continuous 3-0 polyglycolic acid suture. The inferior oblique muscles are reapproximated with a figure-eight 3-0 polyglycolic acid suture, and the external oblique fascia is closed with a continuous 2-0 polyglycolic acid suture.

The skin may be closed with staples or subcutaneous sutures. Use of staples is recommended if the appendix was perforated and skin closure is to be performed. Some authors believe that the skin should be left open in cases of perforated appendicitis, with delayed primary closure performed on postoperative day 4 or 5.

Laparoscopic appendectomy

A urinary bladder catheter is placed, and the surgeon typically stands on the left side of the patient. Video monitors are placed at the patient's right side.

A 12-mm supraumbilical incision is made, followed by placement of the Veress needle. After confirmation of intraperitoneal placement, pneumoperitoneum (15 mm Hg) is established and maintained by using a carbon dioxide insufflator. The Veress needle is replaced with a 5-mm trocar, and a 5-mm 30º laparoscope is inserted into the peritoneal cavity. Alternatively, the 5-mm trocar can be placed directly into the abdominal cavity using an open cutdown approach. This 5-mm port is subsequently upsized to a 12-mm port once the other ports are placed.

Under direct visualization, a 5-mm trocar is inserted into the left lower quadrant (LLQ), and another 5-mm trocar is placed in the suprapubic region. The camera is moved to the LLQ port, and the patient is placed in Trendelenburg position with a leftward tilt to maximize intraperitoneal exposure of the RLQ. Through the suprapubic trocar, a grasper is used to gain control of the appendix. A dissector placed through the supraumbilical port is used to create a small hole in the mesoappendix at the base of the appendix. An endoscopic gastrointestinal anastomosis (GIA) stapler is then used to staple the base of the appendix, and a vascular reload is used to staple across the mesoappendix.

Once the appendix is free, it is removed through the 12-mm port by using an endoscopic retrieval bag. Any free fluid in the abdomen and pelvis is suctioned. Appropriate peritoneal irrigation is then performed. The fascia of the supraumbilical port site is closed with 0 polyglycolic acid suture, and the skin incisions are closed with subcuticular sutures.

Single-incision laparoscopic appendectomy

Single-incision laparoscopic appendectomy (SILA) has been described and has shown to be safe and effective.[54] This procedure is typically performed through the umbilicus via a multichannel trocar. The main benefit of SILA is cosmetic; however, early studies reported longer operating times.[55]

Transvaginal appendectomy

A NOTES (natural orifice transluminal endoscopic surgery) approach, transvaginal appendectomy, has been developed.

Treatment of perforated appendicitis with abscess

Patients with perforated appendicitis and abscess formation or phlegmon may be treated with either immediate operative intervention or initial nonoperative management. Although there are some proponents of immediate surgical intervention, a meta-analysis of 19 studies by Andersson et al found a significantly higher morbidity (odds ratio, 3.3) than with nonsurgical treatment.[56]

With nonoperative management, patients are initially treated with broad-spectrum IV antibiotics alone or in combination with percutaneous aspiration of the abscess or drain placement.[57] IV antibiotics are continued until patients are afebrile for 24 hours, have a return of normal gastrointestinal function, and have a normal WBC count with a normal differential. At this time, they are switched to oral antibiotics for a total antibiotic course of 10-14 days.

Traditionally, interval appendectomy is performed 6-8 weeks later. In view of the low incidence of recurrent appendicitis, the need for routine interval appendectomy has been challenged.[42, 58]

If acute appendicitis is encountered, only one perioperative dose of broad-spectrum antibiotics is needed to decrease the risk of wound infection and abscess formation.[59] Some surgeons prefer to continue antibiotics for 24 hours after appendectomy. A clear liquid diet can be started once the patient has recovered from anesthesia, and diet can be advanced as tolerated.

If gangrenous or perforated appendicitis is encountered, IV antibiotics are continued until the patient is afebrile, has return of bowel function, and has a normal WBC count with a normal differential. Once bowel function returns, clear liquids can be started and the diet advanced as tolerated. In most patients, a nasogastric tube is not needed.[60, 61]


The overall morbidity of appendicitis is approximately 10%. Most perioperative morbidity is caused by infectious complications.

Wound infections occur in approximately 5% of all appendectomies; however, the incidence of this complication is related to the stage of appendicitis. The wound infection rate is 1.4% for nonacute appendicitis, 3% for acute appendicitis, and 10-15% for perforated or gangrenous appendicitis.

Formation of intra-abdominal or pelvic abscess after appendectomy occurs in 2-5% of patients. The incidence is higher for gangrenous or perforated appendicitis (6-8%) than for early or suppurative appendicitis (1-2%).[21]

Other complications include persistent ileus, small-bowel obstruction, and pulmonary complications, such as atelectasis and pneumonia. Deep venous thrombosis, pulmonary embolism, and myocardial infarction may also occur in the early postoperative period.

Long-Term Monitoring

The patient should return to the clinic 1-2 weeks after discharge for wound evaluation and discussion of the pathology.

Full activity may be resumed 2 weeks after an appendectomy if the procedure was performed laparoscopically or through an RLQ incision. If a midline incision was used, activity should be limited for 6 weeks.



ACR Appropriateness Criteria for Imaging in RLQ Pain/Suspected Appendicitis

In 2018, the American College of Radiology (ACR) issued revised recommendations for imaging in patients with right-lower-quadrant (RLQ) pain and suspected appendicitis.[20]

For patients with RLQ pain, fever, leukocytosis, and suspected appendicitis, initial imaging recommendations include the following:

  • Usually appropriate - Computed tomography (CT) of abdomen and pelvis with intravenous (IV) contrast
  • May be appropriate - CT of abdomen and pelvis without IV contrast; ultrasonography (US) of abdomen; magnetic resonance imaging (MRI) of abdomen and pelvis without and with IV contrast; US of pelvis; MRI of abdomen and pelvis without IV contrast 
  • Usually not appropriate - CT of abdomen and pelvis without and with IV contrast; radiography of abdomen; fluoroscopy contrast enema; technetium 99m (Tc-99m) white blood cell (WBC) scan of abdomen and pelvis 

For patients with RLQ pain, fever, leukocytosis, possible appendicitis, and an atypical presentation, initial imaging recommendations include the following:

  • Usually appropriate - CT of abdomen and pelvis with IV contrast
  • May be appropriate - CT of abdomen and pelvis without IV contrast; US of abdomen; MRI of abdomen and pelvis without and with IV contrast; US of pelvis; MRI of abdomen and pelvis without IV contrast 
  • Usually not appropriate - CT of abdomen and pelvis without and with IV contrast; radiography of abdomen; fluoroscopy contrast enema; Tc-99m WBC scan of abdomen and pelvis

 For pregnant women with RLQ pain, fever, leukocytosis, and suspected appendicitis, initial imaging recommendations include the following:

  • Usually appropriate - US of abdomen; MRI of abdomen and pelvis without IV contrast
  • May be appropriate - US of pelvis; CT of abdomen and pelvis with IV contrast; CT of abdomen and pelvis without IV contrast
  • Usually not appropriate - MRI of abdomen and pelvis without and with IV contrast; CT of abdomen and pelvis without and with IV contrast; radiography of abdomen; Tc-99m WBC scan of abdomen and pelvis; fluoroscopy contrast enema